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arXiv 0908.2046cond-mat.soft
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玻璃化转变前后分子液体的快慢动力学之间的联系

Connection between slow and fast dynamics of molecular liquids around the glass transition

K. Niss, C. Dalle-Ferrier, B. Frick, D. Russo, J. Dyre, C. Alba-Simionesco

摘要:

用中子散射法测量了不同温度和压力下几种分子玻璃形成液体的均方位移(MSD)。MSD在所研究的压力下沿着玻璃化转变线是不变的,从而为任何给定的液体建立了一个“内在的”林德曼标准。当在大约4纳秒的时间尺度上评估MSD时,发现MSD的温度依赖性和液体的脆性之间存在一对一的联系,但当在更短的时间内评估MSD时,这种联系并不成立。研究结果进行了讨论的弹性模型和松弛的作用,并解决慢和快的动态之间的相关性。

英文摘要:

The mean-square displacement (MSD) was measured by neutron scattering at various temperatures and pressures for a number of molecular glass-forming liquids. The MSD is invariant along the glass-transition line at the pressure studied, thus establishing an ``intrinsic'' Lindemann criterion for any given liquid. A one-to-one connection between the MSD's temperature dependence and the liquid's fragility is found when the MSD is evaluated on a time scale of approximately 4 nanoseconds, but does not hold when the MSD is evaluated at shorter times. The findings are discussed in terms of the elastic model and the role of relaxations, and the correlations between slow and fast dynamics are addressed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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